| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical head and an optical disk unit having the stable reproduction output over the using temperature range, with which the S/N ratio of the reproduced signal becomes high and the high recording density of the optical disk is obtainable, in the case the signal is reproduced by using the self-combination effect of a semiconductor laser. SOLUTION: A resonator of the semiconductor laser is constituted of a high reflection film 2d on the rear end surface of an activated medium 2 for semiconductor laser and a reflecting/transmitting film 7 formed on the surface 6c to be converged of a transparent medium 6 for convergence. The reflecting/ transmitting film 7 is provided with a transmittance such that the intensity difference of the signals detecting the lights returned from a recording medium 8a is increased in accordance with the recorded information of the recording medium 8a. Thus, the reproduced signal having the high S/N ratio is obtained even though a light spot 9a is made smaller. |
